FRACTURE OF NECK OF THE FEMUR

Dr. Prateek Singh (intern)

Department Of Orthopedics B.P. Koirala Institute of Health Sciences

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INTRODUCTION The structure of the head and neck of

femur is developed for the transmission of body weight efficiently, with minimum bone mass, by appropriate distribution of the bony trabeculae in the neck.  The tension trabeculae and compression trabeculae along with the strong calcar femorale on the medial cortex of the neck of the femur form an efficient system to withstand load bearing and torsion under normal stresses of locomotion and weight bearing.

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ANATOMY OF NECK OF FEMUR

Neck connects head with shaft and is about 3.7 cm long.

It makes angle with the shaft 130+/- 7 degree

( less in female due to their wider pelvis). It facilitate movements of hip joint.

It is strengthened by calcar femorale (bony thickening along its concavity).

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2 borders and 2 surfaces -upper border –concave and horizontal

meets the shaft at greater trochanter. -lower border – straight and oblique meet

the shaft at lesser trochanter.

-anterior surface- flat .meet shaft at intertrochanteric line . Entirely intra capsular.

-posterior surface- convex from above downwards and concave from side to side.meets shaft at intertrochanteric crest.it is crossed by horizontal groove for tendon of obturator externus.

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Blood sypply Crock described the arteries of the

proximal end of the femur in three groups

(a) an extracapsular arterial ring located at the base of the femoral neck;

(b) ascending cervical branches of the extracapsular arterial ring on the surface of the femoral neck (known as retinacular arteries)

(c) the arteries of the ligamentum teres

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a) The extracapsular arterial ring is formed posteriorly by a large branch of the medial femoral circumflex artery and anteriorly by branches of the lateral femoral circumflex artery .

The superior and inferior gluteal arteries also have minor contributions to this ring

b) The ascending cervical arteries can be divided into four groups (anterior, medial, posterior, and lateral) based on their relationship to the femoral neck.

lateral group provides most of the blood supply to the femoral head and neck.

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c) The artery of the ligamentum teres is a branch of the obturator or the medial femoral circumflex artery

only small & variable amount of femoral head is nourished by artery of ligamentum teres.

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Vascular anatomy of the femoral head and neck

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Anterior aspect

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PATHO-ANATOMY Most fracture are displaced with distal fragment – externally rotated,

adducted, and

proximally migrated. These displacement are less marked

than in intertrochanteric fracture because the capsule of hip joint is attached to distal fragment and prevent extreme rotation and displacement of distal fragment.

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Displacement of the lower bone fragment caused by the pull of the powerful muscles.

In particular the outward rotation of the leg so that the foot characteristically points laterally. (GM) gluteus maximus; (PI) piriformis; (OI) obturator internus; (GE) gemelli; (QF) quadratus femoris; (RF) rectus femoris; (AM) adductor muscles; (HS) hamstring muscles

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ETIOLOGY

Commonest site of # in elderly(7th /8th decade).

Post menopausal women, osteomalacia, diabetes, stroke, alcoholism, chronic debilitating disease.

Old people– weak muscle, poor balance – increased tendency to fall.

Fall directly onto greater trochanter. Fall from height, RTA

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CLASSIFICATION

-ANATOMICAL LOCATION -subcapital -transcervical -basicervical (base of the

neck fracture)

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-PAUWEL

This is based on the angle of fracture from the horizontal

Type I: 30 degrees Type II: 50 degrees Type III: 70 degrees

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As the fracture progresses from type 1 to type 3, the obliquity ofthe fracture fracture line increases, thus the shear force at the fracture site increases

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-GARDEN

This is based on the degree of valgus displacement

Type I: Incomplete/valgus impacted Type II: Complete and nondisplaced on AP

and lateral views Type III: Complete with partial displacement;

trabecular pattern of the femoral head does not line up with that of the acetabulum

Type IV: Completely displaced; trabecular pattern of the head assumes a parallel orientation with that of the acetabulum

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-Orthopaedic Trauma Association (OTA) Classification

B1 group fracture is nondisplaced to minimally displaced subcapital fracture

B2 group includes transcervical fractures through the middle or base of the neck

B3 group includes all displaced nonimpacted subcapital fractures

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MECHANISM OF INJURY Low-energy trauma (most common

in older patients) - Direct: A fall onto the greater

trochanter (valgus impaction) or forced external rotation of the lower extremity impinges an osteoporotic neck onto the posterior lip of the acetabulum (resulting in posterior comminution).

- Indirect: Muscle forces overwhelm the strength of the femoral neck

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High-energy trauma- accounts for femoral neck fractures in both younger and older patients, such as motor-vehicle accident or fall from a significant height.

Cyclical loading-stress fractures: These are seen in athletes, military recruits, ballet dancers; patients with osteoporosis and osteopenia are at particular risk.

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CLINICAL PRESENTATIONS

H/O fall from height. nonambulatory on presentation

(EXCEPT impacted fracture patient may still be able to walk)

shortening and external rotation of the lower extremity.

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CLINICAL EVALUATION

Pain is evident on range of hip motion, with possible pain on axial compression and tenderness to palpation of the groin.

Tenderness over Scarpa`s triangle Active SLR not possible

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DIAGNOSIS

Situations in which femoral neck fracture may be missed-

Stress fractures- elderly patient with unexplained pain in the hip should be considered to have stress fracture until proven otherwise.

Undisplaced fracture-impacted fracture may be difficult to visualise on plain x-ray.

Painless fracture-a bed ridden patient may develop a silent fracture.

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Multiple fractures-patient with a femoral shaft fracture may also have a hip fracture which is easily missed unless the pelvis is x rayed.

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RADIOGRAPHIC EVALUATION

An anteroposterior (AP) view of the pelvis both hip in 15 ° internal rotation and a cross-table lateral view of the involved proximal femur are indicated

Technetium bone scan or preferably magnetic resonance imaging may be of clinical utility in delineating nondisplaced or occult fractures that are not apparent on plain radiographs.

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The Importance of a True AP Hip Position

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Cross table view

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Modified Rolled Lateral HipIII(Modified Friedman Method)

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The patient is positioned as shown above with a slightly raised knee (15-20 degrees) and a smaller cephalic tube angle (15-20 degrees).

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Shenton's Line

Shenton's line is a line formed by the inferior aspect of the superior pubic ramus and the medial aspect of the upper femur. Shenton's line should describe a smooth curve. If there is any sharp angulation of Shenton's line the patient could have a neck of femur fracture. An abnormal Shenton's line can be the most obvious indicator of a patient's fractured neck of femur demonstrated on an AP pelvis /hip image.

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TREATMENT

Goals of treatment are to minimize patient discomfort, restore hip function, allow rapid mobilization by obtaining

early anatomic reduction and stable internal fixation or prosthetic replacement.

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In children- close reduction and Hip spica.If not reduced then ORIF with Moore`s

pins.

Adults impacted or garden

type 1 & 2 Non-operative Treatment- bed rest

for elderly person whose medical condition carries an excessively high risk of mortality from anesthesia and surgery

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Operative Treatment- include the following

- Internal fixation with multiple cancellous lag screws.(preffered treatment)

- Sliding hip screw – advantages- 1) biomechanical strength greater

than multiple cancellous screws. 2) minimization of risk of

subsequent subtrochanteric fracture secondary to a stress riser effect.

3) placement of compression across the fracture at the time of reduction

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Disadvantages- 1) stabilization include a larger

surgical exposure 2) potential to create rotational

malalignment of the femoral head at the time of screw insertion.

Fracture of the femoral neck

stabilized with three well-placed, 6.5-mm, short threaded cancellous lag screws.

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displaced or garden type 3& 4 age less than 60 years- internal fixation by1)Multiple cancellous screw-most

commonly used.2)Dynamic hip screw (DHS)3)smith peterson nail (S.P. nail)

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age more than 60 years normal hip- Hemiarthroplasty with

Austin-Moore prosthesis.

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Indications for hemiarthroplasty

Comminuted, displaced femoral neck fracture in the elderly

Pathologic fracture Poor medical condition Poorer ambulatory status before

fracture Neurologic condition (dementia,

ataxia, hemiplegia, parkinsonism)

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Advantages of Hemiarthroplasty over open reduction and internal fixation :

1) It may allow faster full weight bearing2) It eliminates nonunion, osteonecrosis,

failure of fixation risks .

Disadvantages:3) It is a more extensive procedure with

greater blood loss4) A risk of acetabular erosion exists in

active individuals

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preexisting degenerative condition -total hip replacement

Indications osteoarthritis, rheumatoid arthritis, severe osteoporosis pathologic conditions with acetabular

involvement such as Paget's disease

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COMPLICATIONS

General- 1. Deep vein thrombosis2. Pulmonary embolism3. Pmeumonia4. Bed sores

Osteoarthritis Avascular necrosis Non-union

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cause of AVN and non-union Tearing the capsular vessels the

injury deprives the head its main blood supply

Intra articular bone has only flimsy periosteum and no contact with soft tissue which could promote callus formation

Synovial fluid prevents clotting of the fracture hematoma

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refrences

Essential orthopaedics – J. Maheshwari Handbook of Fractures- Kenneth J. Koval

M.D & Joseph D.

Zuckerman M.D Rockwood & Green's Fractures in Adults- Robert W.

Bucholz MD, James D.

Heckman MD, Charles M. Court-

Brown MD. Apleys System of orthopaedics and

fractures David

Warwick MD.

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GREY’S ANATOMY B.D. chaurasia’s human anatomy

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THANK YOU